Hydraulic control for drilling rigs



Feb. 22, 1938. w. F. MCMURRY ET AL HYDRAULIC CONTROL FOR DRILLING HIGS Filed Aug. 14, 1935 3 Sheets-Sheet l Feb. 22, 1938. w. F. MGMURRY ET AL HYDRAULIC CONTROL FOR DRILLING RIGS Filed Aug. 14, 1935 3 Sheets-$heet 2 awe/who've "(Fr/WW G. FP/IlY/f,

Feb. 22, 1938. w. F. M MURRY ET AL 2,109,297

HYDRAULIC CONTROL FOR DRILLING HIGS Filed Aug. 14, 1935 5 Sheets-Sheet 3 Patented Feb. 22, 1938 UNITED STATES HYDRAULIC CONTROL FOB DRILLING 3168 William F. McMnn-y and George F. Phillips,

Tulsa, Okla., assignors to Scientific Engineerin; Corporation, Tulsa, Okla.

Application August 14,

10 Claims.

Our invention consists in new and useful improvements in a hydraulic control for drilling rigs and has for its object to provide a device of this character operated by gases, vapors, liquids or other fluids under pressure for automatically maintaining a regulated pull on the drilling line and thereby supporting a portion of the weight of the drilling tools to allow the unsupported portion thereof to maintain a regulated pressure force on the bit for drilling purposes.

Another object-oi our invention is to provide automatic means for advancing the drilling tools into the hole at a uniform rate of feed, the rate of such advancing being such that a uniform weight is carried on the tools continuously.

Heretofore, numerous efforts have been made to devise methods and apparatus for paying out the dead end of the drill line and retrieving it with a drum on which the line has been spooled, but such efforts have proven unsuccessful due to the fact that there was no insurance of uniformity in the feed of the tools. In our improved structure, a hydraulic cylinder is employed for paying out and retrieving the dead end of the line, said cylinder being equipped with a piston and piston rod to which the dead end of the line is fastened. A uniform fluid pressure is maintained in the cylinder at all times by constantly charging to the cylinder 9. suitable fluid under a predetermined pressure and automatically regulating the discharge of fluid from said cylinder.

with the above and other objects in view which will appear as the description proceeds, our invention consists in the novel features herein set forth. illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Fig. 1 is a diagrammatic view of the entire hook-up.

Fig. 2 is a view in side elevation showing our improved apparatus installed on a well drilling derrick.

Fig. 3 is an enlarged vertical sectional view of the cylinder and piston arrangement.

Fig. 4 is an enlarged plan view of the automatic pressure control equipment, and

Fig. 5 is an end view of the latter.

In the drawings, i represents a conventional drilling rig or derrick having the usual derrick legs 2 and floor 3, a suitable pulley arrangement 4 being carried at the upper extremity of the derrick over which the cables or lines 5 are adapted to pass. A traveling block 6 and hook I for supporting the drilling string 8 is carried by the line i at an intermediate point, in the usual manner and as clearly shown in Fig. 2. The drill string 8 may be rotated in the conventional manner by 1935, Serial N0. 36,187

rotary table 3' with which it may have the usual splined or other conventional connection. One end 50. of the cable 5 is secured to the drum D of the draw-works shown diagrammatically in Fig. 1 and of conventional structure said drum being located behind the fluid pressure control assembly 9, (Fig. 2). The other or dead end 5b of the cable or line 5 is secured to the outer end of a piston rod it which extends through a suitable stufling box H in the upper end of a hydraulic cylinder l2, a piston I! being located in said cylinder and operatively connected to the piston rod II! as shown in Fig. 3.

By means of a ring it or other suitable means in the lower extremity of the cylinder It, said cylinder is secured to the floor 3 of the derrick and supported in a plane substantially parallel to that of one of the legs 2 of the derrick by means of a clamp or the like l5, whereby the cylinder, piston and piston rod are in the direct line of pull of the dead end of the cable 5.

A conduit i6 is connected into one side of the cylinder l2 above the piston l3 and leads from a suitable source of fluid pressure in the assembly 9, hereinafter described more in detail, and a second conduit I1 preferably provided with a ball check valve Iii is connected into the other side of the cylinder I! for conducting pressure fluid from the cylinder and returning it to its source, also hereinafter described in detail. The bottom of the cylinder is provided with a vent IQ for placing the underside of the piston in communication with the atmosphere so that the only effective pressure on piston I 3 will be that of the fluid pressure in the upper portion of cylinder i2.

The pressure control assembly 9, referring to Figs. 1, 3 and 4, comprises a fluid tank 20 on the top of which is supported a prime mover 2| which may be in the form of a steam turbine, having an inlet conduit 23 and a discharge conduit 22, a suitable controlling valve 24 being provided ad- Jacent to the inlet line. In line with the shaft 25 of the prime mover II, we provide a pump 2B 01' any conventional design and connected at its intake side into the tank 20 by a conduit 21 which extends through the top of the tank and downwardly therein to a point adjacent the bottom thereof. In the event that a liquid is used as the pressure medium in the tank 20, a strainer 28 may be provided at the lower open end of the conduit 21 as shown in Fig. l and in dotted lines in Fig. 5.

The discharge side of the pump 26 is connected by a conduit 28 and T 30 to the conduit l8 which leads to the intake side of the hydraulic cylinder into a line 35 (Figs. 1 and 5), the latter terminating in communication with a line 36 which leads back to the tank 20 through connection 31.

Thus when starting up this apparatus, the throttle valve 33 is opened, and the pump 26 operated by the prime mover 2| draws fluid from the tank through line 21 and immediately returns the same through valve 33, line 32, line 35, line 36 and connection 31 to the tank. However, as soon as the pump is in full operation, the throttle valve 33 is closed and the fluid is forced through line I6 into the cylinder I2.

The return line I1 from the cylinder I2 terminates in a T-connection 38, one end of which is connected by line 39 to a pressure control valve 40, a valve 4| being interposed in the line 33 anterior to the inlet side of the valve 40. The discharge side of valve 40 is connected by line 42 and T-connection 43 to the return connection 31 leading back into the tank 20, a second valve 44 being provided in line 42 posterior to the pressure control valve 40.

A conventional pressure regulator 45 is operatively connected to the pressure control valve 40. This pressure regulator and control valve assembly is preferably of the type which is controlled by a pilot valve in the form of a Bourdon tube BI (Fig. 1) located in the diaphragm chamber of the regulator above the diaphragm 45a, said Bourdon tube being responsive to the pressure in the cylinder I2 and return conduit I1.

The operating medium for the valve regulator 45 is preferably compressed air provided by a compressor 46 and stored in an air flask 41 equipped with any suitable relief valve 41a. An air line 48 having a pressure gauge 49 leads from the air flask 41 to the diaphragm chamber of the regulator 45 where it terminates in a nozzle 48a. The free end of the Bourdon tube 6| carries a valve head adapted to close the nozzle 4311 when the tube is under pressure and open the nozzle upon a reduction in pressure. A line 50 connected to the Bourdon tube 6| in the diaphragm chamber of regulator 45 by means of a coupling 5|, leads from a T 52 which is connected into the return line I1 by means of a pipe 53, whereby the pressure fluctuations in line I1 and cylinder I2 connected thereto are transmitted to the Bourdon tube which in turn controls the operation of the pressure regulator and pressure control valve 40 by opening or closing the nozzle 48a to build up or cut down the pressure in the diaphragm chamber.

The valve 40 is provided with an inner valve 40a connected to the diaphragm 45a. by a valve stem 40!). The inner valve structure is of the type which closes upon downward movement by the diaphragm and stem and opens upon the release of pressure from the diaphragm chamber, a conventional coil spring or the like being provided for normally retaining the valve in open position.

A suitable pressure gauge 54 is mounted on the connection 5| in operative communication with the fluid return line I1 through pipes 50 and 53, said gauge preferably having a double dial as shown in Figs. 1 and 5, the outer dial being graduated in counterclockwise direction and rotatable on the inner dial by manual control 62.

In order to facilitate the removal of the pressure regulator 45 and pressure control 40 for repairs, we provide a by-pass which consists of pipes 55, 56, 51 and 58 leading from the T 52 and terminating in a T is coupled to pipe 36 which, through T 43 and connection 31, discharges the pressure fluid back into the tank 20 as will be hereinafter referred to more in detail in describing the operation of our improved apparatus. A valve 50 is provided in the line 56, the manipulation of said valve together with valves 4| and 44 adjacent the pressure control valve 40, controlling the direction of flow either through the pressure control valve or the by-pass lines.

Having thus described the construction and assembly of our improved hydraulic control, its operation is as follows:

Assuming that the string of tools has been lowered into the hole by the conventional drawworks and that the hole is 3000 feet deep, there being 150 joints of drill pipe weighing 300 pounds each, making a total weight of 45,000 pounds of drill pipe in the hole. Say for example that 5000 pounds is to be carried on the bit, thus leaving 40,000 pounds to be supported by the traveling block 6.

Let us assume that the traveling block is rigged with four lines, each carrying approximately onequarter of 40,000 pounds or 10,000 pounds and that the efiective area of the piston I3 in the hydraulic cylinder I2 is 30 square inches. Thus the pressure per square inch to maintain 5000 pounds on the bit is 10,000 pounds divided by 30, or 333 pounds per square inch.

Now then, by setting the valve regulator 45 of the pressure control valve 40 at 333 pounds, the weight on the bit will be maintained at 5000 pounds. As before stated, the pressure gauge 54 is provided with a double dial, the outer dial being graduated in counterclockwise direction and rotatable on the inner dial. Just before the tools are landed on the bottom of the hole, the outer dial is rotated by the control 62 until the zero point co-incides with the pointer. The pressure regulator 45 and valve 40 are then regulated until the pointer drops back to a number on the outer dial at which it is desired to carry the weight on the tools, in the present instance, 333 pounds.

Assuming now that the pump 26 driven by the prime mover 2| is in full operation, fluid is continuously pumped from tank 20 through line 21, line 29 and line I5 into the upper portion of the hydraulic cylinder I2, the throttle valve 33 having been closed as soon as the pump was in full operation. From the cylinder l2, the fluid flows back through the return line I1, and assuming that the valve on the by-pass is closed and valves 4| and 44 opened, said returning fluid flows down through line 39 through the pressure control valve 40, through line 42 and back into the tank 20 through the return connection 31 (see Figs. 1 and 5). It will be noted that this pressure control valve 40 and the regulator 45 may be set to bleed the pressure from the cylinder I2 at any desired pressure, for example, from 10 to 1000 pounds per square inch.

With fluid being forced continuously through the cylinder at a predetermined pressure as the line is paid 011 of the draw-works, when the tools are lowered in the hole so that they rest with more weight on the bottom than that for which the apparatus is set, the pull on the cable 5b, the piston rod I0 and the piston I3 will be reduced. This in turn causes the fluid pressure in the fluid line I1 leading from the cylinder to drop below the pressure for which the pressure control valve 40 is set. Hence the regulator 45 which is controlled by response to the pressure in the return line l1 by means of connection 50 and the pilot valve assembly 5|48a, permits a valve operating fluid such as compressed air fed from the air flask I! through line 48, to build up sufllcient pressure on the diaphragm 45a in the pressure regulator to throttle or close the valve ill. The fluid in line H and in the hydraulic cylinder will then accumulate and increase the pressure in the cylinder, forcing the piston downwardly until suiflcient line has been retrieved to place enough weight on the piston I! to increase the pressure in the fluid line H from the cylinder to the pressure for which the pressure control valve and regulator are set. Thereupon the valve ill will again bleed oil? the fluid and retain the pressure at the desired amount.

In the event repairs are necessary on the pressure control valve or regulator, valves ll and 44 may be closed and valve 60 opened while the said parts are being repaired. During this time, careful manipulation of the throttlevalves 33 and 60 will maintain the pressure in the line IT at the desired point.

It will thus be seen that we have devised a novel and eiflcient hydraulic control system which does not depend upon the table speed to feed the tools into the hole but on the contrary maintains a definite bit pressure regardless 01 what the table speed may be, due to the arrangement and manual setting of the pressure control valve as hereinbefore described. Obviously this system insures the maintenance 01' a uniform weight on the drilling tools until the setting of the pressure control valve is changed.

It will be further noted that with our improved hydraulic control system we maintain this regulated pull on the drilling line by permitting the fluid to escape from the hydraulic cylinder at a regulated pressure instead of at a regulated volume.

From the ioregoing it is believed that the construction operation and advantages of our invention may be readily understood by those skilled in the art, without further description, it being borne in mind that numerous changes may be madein the details disclosed without departing from the spirit of the invention as set forth in the following claims.

What we claim and desire to secure by Letters Patent is:

1. Apparatus for maintaining a predetermined drilling weight on a string of drilling tools, including means controlled by variations in said predetermined weight to compensate i'or said variations, said means comprising a flxed hydraulic cylinder, a piston and piston rod in said cylinder, means for securing the dead end 01' a tool supporting cable to said piston rod, a pump for continuously delivering fluid to said cylinder under a constant pressure, separate means for continuously discharging fluid from said cylinder, and means responsive to the pressure in said cylinder for controlling said discharge means, the pressure in said cylinder being in turn responsive to variations oi said predetermined drilling weight.

2. Apparatus for maintaining a predetermined drilling weight on a string of drilling tools, including means controlled by variations in said predetermined weight to compensate for said variations, said means comprising a fixed hydraulic cylinder, a piston and piston rod in said cylinder. means for securing the dead end oi a tool supporting cable to said'piston rod, 9. fluid supply valve for controlling said fluid return, a separate source of pressure fluid for operating said motor valve, and means responsive to the pressure in said cylinder for controlling the operation 01' said motor valve, the pressure in said cylinder being in turn responsive to variations of said predetermined drilling weight.

3. Apparatus as claimed in claim 2 wherein said separate source of pressure fluid comprises an air compressor and air flask in communication with the operating member of said motor valve.

4. Apparatus as claimed in claim 2 wherein said fluid return conduit is provided with a valve controlled by-pass adjacent to said motor valve whereby the latter may be removed from the system without interrupting said fluid return.

5. Apparatus as claimed in claim 2 including a duplex gauge associated with said motor valve and responsive to the pressure in said cylinder, said gauge comprising a fixed dial calibrated in one direction, and a rotatable dial co-axial with said flxed dial and calibrated in the opposite direction, the adjustment of said rotatable dial with respect to said flxed dial indicating the weight for which said motor valve is set to operate.

6. A fluid pressure system for maintaining constant the pressure in a hydraulic cylinder against a fluctuating force, comprising a fluid supply tank in communication with said cylinder, means ior continuously pumping fluid from said tank to said cylinder, an independent conduit for continuously returning fluid to said tank from said cylinder, a motor valve for controlling said fluid return, a separate source of pressure fluid for operating said motor valve, and means responsive to the pressure in said cylinder for controlling the operation o1 said motor valve.

7. A fluid pressure system as claimed in claim 6 wherein said separate source of pressure fluid comprises an air compressor and air flask in communication with the operating member of said motor valve.

8. A fluid pressure system as claimed in claim 6 wherein said fluid return conduit is provided with a valve controlled by-pass adjacent to said motor valve whereby the latter may be removed from the system without interrupting said fluid return.

9. A fluid pressure system as claimed in claim 6 including a duplex gauge associated with said motor valve and responsive to the pressure in said cylinder, said gauge comprising a fixed dial calibrated in one direction, and a rotatable dial co-axial with said flxed dial and calibrated in the opposite direction, the adjustment oi said rotatable dial with respect to said flxed dial indicating the weight for which said motor valve is set to operate.

10. The combination with a hydraulic cylinder having a piston and piston rod therein, of a fluid system for maintaining constant the pressure in said cylinder against a fluctuating force applied to said piston rod, comprising a fluid supply tank in communication with said cylinder, means for continuously pumping fluid from said tank to said cylinder under a predetermined pressure, an independent conduit for continuously returning said fluid from said cylinder to said tank, a valve for controlling said return of fluid, and pressure actuated means responsive to the pressure in said cylinder for controlling the operation of said valve, whereby a predetermined pressure force is maintained on said piston.

WILLIAM F. McMURRY. GEO. I". PHILIIPS. 

